The present invention relates to a fuel pump having a driven propeller, or impeller wheel, rotatable in a pump housing and in which, in at least one of its end sides, there is arranged a ring of guide vanes defining vane chambers, having a partial-ring-shaped channel arranged in the pump housing in the region of the guide vanes, which channel together with the vane chambers forms a conveyor chamber for conveying a liquid from an inlet channel to an outlet channel.
Such fuel pumps are known as peripheral or lateral channel pumps and are used, for instance, for conveying fuel or wash liquid of a windshield-cleaning system of a motor vehicle. In this case, the guide vanes in the conveyor chamber produce a circulatory flow which extends transverse to the direction of movement of the guide vanes. The fuel pump is characterized by a particularly small need for maintenance. Furthermore, very high conveyor pressures can be produced by the fuel pump. With such a fuel pump, however, readily volatile liquids upon flow into the conveyor chambers, such as, for instance, fuel of solvents of a wash liquid can evaporate and thus form gas bubbles. The gas bubbles are therefore produced more frequently the higher the temperature of the liquid and the lower the pressure in the inlet channel. The gas bubbles lead to a strong reduction in the delivery capacity of the fuel pump. Furthermore, the gas bubbles produce cavitation at the pump housing. This cavitation leads in the long run to a destruction of the wall of the partial-ring-shaped channel and then to a reduced delivery of the fuel pump.
A fuel pump known in practice has several pump stages with a plurality of impeller wheels. In this way, the pressure increase in the fuel pump could take place stepwise, so that a vaporization of the liquid is avoided.
This fuel pump, however, has the disadvantage that several impeller wheels for the production of several pump stages result in a considerable structural expense. The fuel pump in this way consists of a very large number of structural parts which must be aligned to each other expensively and mounted.